Abstract About 175,000 leg and hip fractures each year are treated by implanting a stiff metal rod or intramedullary (IM) nail, through the center of the bone and fixing the ends of the nail to the bone with screws. But placing the locking screws to fix the rod to the bone is difficult. To anchor the nail securely, the surgeon must accurately drill pilot holes through both the bone and locking holes in the nail, while the nail is hidden from view. This challenging task, called distal locking, is typically completed using C-arm fluoroscopy for guidance. Difficulty completing distal locking affects patients by causing longer surgery times, additional blood loss and radiation exposure, possible malrotation of the extremity, and the risk of fracture in the area of the distal holes due to bone defects caused by re-drilling. Surgeons are affected primarily by the repeated radiation exposure, while the challenges lead many general orthopedic surgeons to refer patients to specialists; these surgeries are often only performed by specialists at Level 1 or Level 2 trauma centers. A more accurate and safer way to locate distal holes is needed to improve patient outcomes; a method that is easy to perform could also reduce costs and increase access to care. Based on patented technology, Eclipse Orthopaedics is developing a fluoroscopic targeting device, the Radiographic Targeting Attachment? (RTA) that will put both targeting and drilling capabilities in the surgeons' hands. The RTA combines a small X-ray source and a drill attachment that, when paired with the imager and drill, will become a fluoroscopically-guided drill that locates and drills holes in one operation. Eclipse Orthopaedics' overall SBIR goal is to develop the RTA and license the technology to major trauma suppliers, who will market the RTA as an integral part of their internal fixation product portfolio. In Phase I, Eclipse Orthopaedics will: (Aim 1) Design and build a prototype. Eclipse Orthopaedics and Rose- Hulman Ventures will make improvements to the current prototype and supporting software system in preparation for testing; (Aim 2) Measure bench performance of prototype. Eclipse Orthopaedics will evaluate performance in the lab in preparation for cadaver testing by actual surgeons; and, (Aim 3) Evaluate prototype in simulated surgical procedures. In the simulated surgical procedures, orthopaedic surgeons of different experience and skill levels recruited from area hospitals will perform distal locking of IM nails in cadaveric specimens, comparing the standard technique to the RTA method. At the conclusion of Phase I, Eclipse Orthopaedics will have the key system performance data and more importantly the evaluations of target users of the RTA system. With this information, Eclipse will plan a comprehensive product development schedule to be executed in Phase II. Eclipse Orthopaedics' objective is to develop the RTA and license the technology to major trauma suppliers, who will market the RTA as an integral part of their internal fixation product portfolio.